Air conditioning apparatus and method

ABSTRACT

An air conditioning apparatus provided for supplying conditioned air into a space and including a motor driven fan provided for routing air to be conditioned in heat transfer relation with a relatively cold heat exchange medium. Condensate formed as a result of the cooling of the air is collected in a condensate pan which is positioned beneath the heat exchange coil. A pipe defining a closed circuit and having a volatile fluid therein is operable to transfer the heat produced as a result of the operation of the motor driven fan to warm the condensate prior to its collection in the condensate pan. The warming of the condensate prevents secondary condensate from being formed on the surface of the condensate pan.

United States Patent [191 Lim et al.

[1 1] 3,817,049 [4 June 18, 1974 AIR CONDITIONING APPARATUS AND METHOD [73] Assignee: Carrier Corporation, Syracuse, NY. [22] Filed: Feb. 151973 [21] App]. No.: 332,841

[52] US. Cl 62/80, 62/119, 62/272, 62/277, 62/333 [51] Int. Cl. F2501 21/00 [58] Field of Search 62/277, 275, 272, 81

[5 6] References Cited UNITED STATES PATENTS 2,141,918 12/1938 Knight 62/277 2,440,146 4/1948 Kramer.... 62/277 2,444,667 7/1948 Philipp 62/277 2,526,032 10/1950 La Porte 62/277 2,949,016 8/1960 Thorner.... 62/275 3,225,563 12/1965 Braun 62/277 3,355,908 12/1967 Anglin ..62/277 Primary Examiner-William J. Wye Attorney, Agent, or Firm-J. Raymond Curtin; Barry E. Deutsch [5 7] ABSTRACT An air conditioning apparatus provided for supplying conditioned air into a space and including a motor driven fan provided for routing air to be conditioned in heat transfer relation with a relatively cold heat exchange medium. Condensate formed as a result of the cooling of the air is collected in a condensate pan which is positioned beneath the heat exchange coil. A pipe defining a closed circuit and having a volatile fluid therein is operable to transfer the heat produced as a result of the operation of the motor driven fan to warm the condensate prior to its collection in the condensate pan. The warming of the condensate prevents secondary condensate from being formed on the surface of the condensate pan.

7 Claims, 2 Drawing Figures PATENTEDJun 18 m4 m GE , 1 AIR CONDITIONING APPARATUS AND METHOD BACKGROUND OF THE INVENTION the air below its dew point is warmed to prevent the formation of secondary condensate.

The typical modern building, for example, residence, office, hospital, or school, is generally provided with air conditioning apparatus to supply conditioned air into those spaces within the building usually occupied by people. Many of the air conditioning systems serving such buildings, employ air conditioning apparatus in each of the individual spaces within the common enclosure. Such apparatus are operable to provide conditioned air to meet the individual requirements of each of the occupants of theseparate spaces. When such apparatus are operating to provide cooled air to lower the temperature in the spaces, very often the conditioned air is cooled below its dew point. This results in the formation of condensate. The condensate is generally collected in a suitable pan.

Fan-coil units of the type well known to those skilled in the art, are typical of apparatus that may be employed to provide conditioned air to meet individual requirements. Fan-coil units include a motor driven fan, provided to route air to be conditioned about a heat exchanger having a heat exchange medium flowing therethrough. The air is passed in heat transfer relation with such heat exchange medium. When the heat exchange medium is supplied at a relatively cold temperature, the air is cooled and condensate generally forms on the surface of the heat exchanger. The condensate falls from the heat exchanger into a pan which is positioned beneath the heat exchanger. The condensate thus formed is generally at a relatively cold temperature. The condensate thereby cools the exposed surfaces of the collection pan. Air, passing over the surfaces of the pan is cooled at times so its temperature is decreased below the dew point. Secondary condensate is thus formed on the exposed surfaces of the condensate pan which results in sweating."

Heretofore, it has been the practice, to insulate the outer surfaces of the collection pan to prevent the formation of secondary condensate thereon. However, the application of insulating material on the surfaces of a collection pan is generally a costly operation. In addition, many of the common types of insulating material are not satisfactory for use in environments having human occupants. It has been found that some insulating materials spread fire, or burn so an excess amount of smoke and/or toxic fumes are produced.

Furthermore, the operation of the motor driven fan decreases the overall operating efficiency of the unit. The decrease in efficiency results from the addition of heat, generated by the operation of the motor, to the air supplied to the apparatus prior to its being conditioned. Since the air temperature is increased by the transfer of heat generated as a result of the operation of the motor, additional cooling must be accomplished to reduce the temperature of the air being supplied to the space to a satisfactory level.

SUMMARY OF THE INVENTION It is therefore an object of this invention to' warm condensate produced as a result of the cooling of air being supplied to a space to a sufficient level so as to prevent the formation of secondary condensate on the exposed surfaces of a condensate collection pan.

It is a further object of this invention to increase the operating efficiency of air conditioning apparatus.

It is still another object of this invention to transfer heat developed as a result of the operation of a motor driven fan to condensate formed as a result of the cooling of air below its dew point.

These and other objects of this invention are obtained by providing an air conditioning apparatus operable to supply conditioned air into a space. The apparatus includes a heat exchanger through which a relatively cold heat exchange medium is supplied. Means are provided to route air to be cooled in heat transfer relation with the heat exchange medium flowing through the heat exchanger. The condensate formed as a result of the cooling of the air below its dew point is warmed prior to its collection in a condensate pan. The temperature level of the condensate is increased to prevent the formation of condensate on the exposed surfaces of the collection pan.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. 1 is a front view, partially in section, of an air conditioning apparatus embodying the present invention; and

FIG. 2 is a side view, partially in section, of the air conditioning apparatus disclosed in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is disclosed an air conditioning apparatus of a type to which the present invention relates. The particular apparatus is illustrated as a fan coil unit of the type employed in individual spaces within a common enclosure to provide conditioned air to satisfy the occupants requirements. Other types of air conditioning apparatus may be employed with the invention as hereinafter described in detail.

Air conditioning apparatus 10 includes a housing having front and rear walls 12 and 14, side walls 16 and 18, a bottom wall 20 having an opening 22 therein, and a top wall 21 suitably adapted for the discharge of conditioned air into the space being served by apparatus 10. Air to be conditioned is drawn in through opening 22 and is filtered via air filter 24, suitably positioned in the path of flow of the air.

Air from the space is drawn into the housing through opening 22 via fans 26 and 28, suitably mounted within the housing of apparatus 10-. Fans 26 and 28 are operatively connected via shafts 30 and 32, to a suitable motivating device, such as an electric: motor 34.

A heat exchange coil 36 is provided within the housing. Heat exchange coil 36 has a suitable heat exchange medium, for example water, supplied thereto via inlet 38, from a central refrigeration station (not shown). Depending upon the desired space temperature, the heat exchange medium is either warmed or cooled prior to its delivery to apparatus 1.0 to provide conditioned air at a desired temperature level. After the heat exchange medium flows through the heat exchanger, the medium is returned via outlet 40 to the central station for reconditioning.

A pan 42 is positioned below heat exchange coil 36. Pan 42 is provided to collect condensate formed as a result of the cooling of the air being supplied to the space to a level below its dew point. The reduction of supply air temperature occurs when a relatively cold heat exchange medium is supplied to the heat exchanger.

During normal operation of the air conditioning apparatus, air is drawn in through opening 22 via the operation of fans 26 and 28. Undesirable contaminates entrained within the air are filtered by air filter 24. The air is then routed over the surface of heat exchanger 36, thereby passing in heat transfer relation with the heat exchange medium flowing through the heat exchanger. When a relatively cold heat exchange medium is being provided to the air conditioning apparatus, the air is cooled before being supplied to the space. When a relatively warm heat exchange medium is being supplied to the air conditioning apparatus the temperature of the air is increased to a desired level, prior to its being supplied to the space being conditioned. The conditioned air is discharged from apparatus into the space via suitable openings in top wall 21.

As noted hereinbefore, when the air conditioning apparatus is operating to provide relatively cold air to the space, condensate is formed on the surface of the heat exchanger as a result of the lowering of the temperature of the air below its dew point. The condensate falls from the surface of the heat exchanger and is collected in collection pan 42.

The temperature of the condensate collected in pan 42 is relatively low; therefore, the condensate will cool the exposed surfaces of the pan. Very often the temperature of the surfaces of the pan may be cooled to a relatively low level, so air passing thereover will have its temperature decreased below its dew point, thereby causing secondary condensation to form on the exposed surfaces. The condensate drips from the surfaces of the pan, thereby causing undesirable puddles of water to collect.

Heretofore, it has been the practice to provide insulation on the exposed surfaces of condensate collection pans 42 to prevent undesirable sweating." However, the utilization of insulating material has not been entirely satisfactory.

To eliminate the need for insulating material on the exposed surfaces of pan 42, a pipe or tube 44 is provided. Pipe 44 is preferably wrapped around or otherwise suitably positioned relative to the outer housing of motor 34 and extends substantially along the entire length of the heat exchanger 36. The portion 46 of pipe 44 extending along the length of the heat exchanger is disposed between the lower surface of the heat exchanger and the top of the condensate pan at a point whereat substantially all of the condensate collects on the heat exchanger and falls therefrom. The pipe is thus positioned to intercept the falling condensate. The pipe forms a closed circuit and has a heat transfer fluid, for example a volatile liquid, such as a suitable refrigerant, provided therein.

During the operation of the air conditioning apparatus, heat is generated as a result of the energization of motor 34. The refrigerant in pipe 44 is vaporized due to its absorbing heat generated by the motor. The vaporized fluid passes through the pipe and is then exposed, in portion 46, to the falling condensate droplets. The condensate absorbs heat from the vaporized refrigerant and is thereby warmed. The refrigerant is condensed as a result of the transfer of heat to the condensate. The condensate is thus suitably warmed prior to its entry into pan 42. If desired, pipe 44 may have fins or other similar devices to increase the surface area of the pipe and thus improve the heat transfer between the refrigerant and condensate.

The exposed surfaces of pan 42 are thence maintained at a satisfactory temperature level to prevent the formation of secondary condensate thereon.

Upstanding portions 50 and 52 of pipe 44 are inclined upwardly relative to the surface of the condensate pan to prevent condensate from flowing along the pipe downwardly to the motor.

In addition to the elimination of sweating, the efficiency of operation of the air conditioning apparatus is improved. The heat generated by the operation of motor 34 has heretofore increased the temperature of the air prior to its passing in heat transfer relation with the heat exchange medium flowing through the heat exchange coil. When it has been desired to provide relatively cold air for cooling the space, the addition of heat from the motor, has increased the amount of cooling required to provide conditioned air at a satisfactory temperature level. The utilization of the present invention transfers the heat generated by the operation of the motor to prevent undesirable sweating. In addition, the efficiency of operation of the air conditioning apparatus will be improved since the transfered heat will no longer be available to be absorbed by the air passing through the apparatus.

While the present invention has been shown as being utilized in a fan coil unit, it should be specifically understood that the invention may be employed with other air conditioning apparatus wherein it is desired to warm condensate to prevent sweating" of exposed surfaces of a condensate collection pan.

While we have described and illustrated a preferred embodiment of our invention, our invention should not be limited thereto, but may be otherwise embodied within the scope of the following claims.

We claim:

1. Apparatus for conditioning air to be supplied to a space being conditioned comprising:

heat exchange means having a relatively cold heat exchange fluid flowing therethrough;

means to circulate air in heat transfer relation with said relatively cold heat exchange fluid to lower the temperature of said air to its desired level prior to its delivery to said space;

means positioned beneath said heat exchange means for collecting condensate formed on the surface of said heat exchange means as a result of the cooling of said air; and

means for warming said condensate prior to its passing to said collecting means to prevent said condensate from cooling said collecting means to thereby prevent additional condensate from being formed on the surface of the collecting means, said warming means including a coil having heat transfer fluid contained therein, said heat transfer fluid comprising a volatile liquid, the liquid being vaporized as a result of its passing in heat transfer relation with a source of heat, the volatile liquid thereafter passing in heat transfer relation with said condensate to warm said condensate, the volatile liquid being condensed. 2. Apparatus in accordance with claim 1 wherein said heat source comprises a motor operably connected to said circulating means.

3. Apparatus for conditioning air to be supplied into a space being conditioned comprising:

A. heat exchange means having a relatively cold heat exchange fluid flowing therethrough;

B. means to circulate air in heat transfer relation with said relatively cold heat exchange fluid to lower the temperature of said air to a desired level prior to its delivery to said space, said circulating means including a motor having an outer housing, the operation of said motor causing the temperature of said housing to be increased;

C. a pan for collecting condensate fonned on the surface of said heat exchange means as a result of the cooling of said 'air; and

D. means for transferring the heat from said motor housing to said condensate to raise the temperature of said condensate prior to its passing to said collection pan to prevent said condensate from decreasing the surface temperature of said pan to thereby prevent secondary condensate from being formed on the surface of the pan as a result of the passing of relatively warm air thereover.

4. Apparatus in accordance with claim 3 wherein said transfer means includes a pipe defining a closed circuit and having a volatile fluid contained therein, one end of said pipe being in heat transfer relation with said motor housing and the other end of said pipe being positioned in the path of flow of said condensate to said pan, the volatile fluid absorbing heat from said motor 6 and being vaporized thereby, saidl vaporized fluid passing in heat transfer relation with said condensate, said condensate being warmed thereby and said volatile fluid being condensed.

5. A method of operating an air conditioning apparatus provided for supplying conditioned air into a space, the apparatus including a motor driven fan, comprising the steps of:

A. actuating the motor driven fan to pass relatively warm air to be conditioned in heat transfer relation with a relatively cold heat exchange medium to cool the air to a desired temperature level;

B. transferring heat created as a result of the operation of the motor driven fan to condensate formed as a result of the cooling of the air to thereby warm the condensate to a desired level;

C. collecting the warmed condensate, the temperature level of the condensate having been increased to prevent secondary condensate from being formed on the surface of the collection device; and

D. delivering the cooled air into the space being conditioned.

6. The method in accordance with claim 5 wherein the transfer of the heat from the motor driven fan to the condensate is accomplished via a pipe having a heat transfer fluid contained therein, the end of said pipe warm said condensate and condense said liquid. 

1. Apparatus for conditioning air to be supplied to a space being conditioned comprising: heat exchange means having a relatively cold heat exchange fluid flowing therethrough; means to circulate air in heat transfer relation with said relatively cold heat exchange fluid to lower the temperature of said air to its desired level prior to its delivery to said space; means positioned beneath said heat exchange means for collecting condensate formed on the surface of said heat exchange means as a result of the cooling of said air; and means for warming said condensate prior to its passing to said collecting means to prevent said condensate from cooling said collecting means to thereby prevent additional condensate from being formed on the surface of the collecting means, said warming means including a coil having heat transfer fluid contained therein, said heat transfer fluid comprising a volatile liquid, the liquid being vaporized as a result of its passing in heat transfer relation with a source of heat, the volatile liquid thereafter passing in heat transfer relation with said condensate to warm said condensate, the volatile liquid being condensed.
 2. Apparatus in accordance with claim 1 wherein said heat source comprises a motor operably connected to said circulating means.
 3. Apparatus for conditioning air to be supplied into a space being conditioned comprising: A. heat exchange means having a relatively cold heat exchange fluid flowing therethrough; B. means to circulate air in heat transfer relation with said relatively cold heat exchange fluid to lower the temperature of said air to a desired level prior to its delivery to said space, said circulating means including a motor having an outer housing, the operation of said motor causing the temperature of said housing to be increased; C. a pan for collecting condensate formed on the surface of said heat exchange means as a result of the cooling of said air; and D. means for transferring the heat from said motor housing to said condensate to raise the temperature of said condensate prior to its passing to said collection pan to prevent said condensate from decreasing the surface temperature of said pan to thereby prevent secondary condensate from being formed on the surface of the pan as a result of the passing of relatively warm air thereover.
 4. Apparatus in accordance with claim 3 wherein said transfer means includes a pipe defining a closed circuit and having a volatile fluid contained therein, one end of said pipe being in heat transfer relation with said motor housing and the other end of said pipe being positioned in the path of flow of said condensate to said pan, the volatile fluid absorbing heat from said motor and being vaporized thereby, said vaporized fluid passing in heat transfer relation with said condensate, said condensate being warmed thereby and said volatile fluid being condensed.
 5. A method of operating an air conditioning apparatus provided for supplying conditioned air into a space, the apparatus including a motor driven fan, comprising the steps of: A. actuating the motor driven fan to pass relatively warm air to be conditioned in heat transfer relation with a relatively cold heat exchange medium to cool the air to a desired temperature level; B. transferring heat created as a result of the operation of the motor driven fan to condensate formed as a result of the cooling of the air to thereby warm the condensate to a desired level; C. collecting the warmed condensate, the temperature level of the condensate having been increased to prevent secondary condensate from being formed on the surface of the collection device; and D. delivering the cooled air into the space being conditioned.
 6. The method in accordance with claim 5 wherein the transfer of the heat from the motor driven fan to the condensate is accomplished via a pipe having a heat transfer fluid contained therein, the end of said pipe being in heat transfer relation with said motor.
 7. The method in accordance with claim 6 wherein said heat transfer fluid comprises a volatile liquid; the volatile liquid being vaporized as a result of absorbing heat from said motor, the vaporized liquid thereafter passing in heat transfer relation with said condensate to warm said condensate and condense said liquid. 